X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-web.git/blobdiff_plain/fbb16ba8e40d6b99bc7501faf4ebd934631900ca..f3c1b256ad0f930d2f7fc623ad538692a3829979:/templates/main.py

diff --git a/templates/main.py b/templates/main.py
index e2a88b3..915b5eb 100755
--- a/templates/main.py
+++ b/templates/main.py
@@ -12,9 +12,11 @@ import base64
 import sha
 import hmac
 import datetime
+import StringIO
+import getafsgroups
 
-print 'Content-Type: text/html\n'
-sys.stderr = sys.stdout
+errio = StringIO.StringIO()
+sys.stderr = errio
 sys.path.append('/home/ecprice/.local/lib/python2.5/site-packages')
 
 from Cheetah.Template import Template
@@ -22,8 +24,46 @@ from sipb_xen_database import *
 import random
 
 class MyException(Exception):
+    """Base class for my exceptions"""
     pass
 
+class InvalidInput(MyException):
+    """Exception for user-provided input is invalid but maybe in good faith.
+
+    This would include setting memory to negative (which might be a
+    typo) but not setting an invalid boot CD (which requires bypassing
+    the select box).
+    """
+    def __init__(self, err_field, err_value, expl=None):
+        MyException.__init__(self, expl)
+        self.err_field = err_field
+        self.err_value = err_value
+
+class CodeError(MyException):
+    """Exception for internal errors or bad faith input."""
+    pass
+
+class Global(object):
+    def __init__(self, user):
+        self.user = user
+
+    def __get_uptimes(self):
+        if not hasattr(self, '_uptimes'):
+            self._uptimes = getUptimes(Machine.select())
+        return self._uptimes
+    uptimes = property(__get_uptimes)
+
+g = None
+
+def helppopup(subj):
+    """Return HTML code for a (?) link to a specified help topic"""
+    return '<span class="helplink"><a href="help?subject='+subj+'&amp;simple=true" target="_blank" onclick="return helppopup(\''+subj+'\')">(?)</a></span>'
+
+
+global_dict = {}
+global_dict['helppopup'] = helppopup
+
+
 # ... and stolen from xend/uuid.py
 def randomUUID():
     """Generate a random UUID."""
@@ -31,21 +71,90 @@ def randomUUID():
     return [ random.randint(0, 255) for _ in range(0, 16) ]
 
 def uuidToString(u):
+    """Turn a numeric UUID to a hyphen-seperated one."""
     return "-".join(["%02x" * 4, "%02x" * 2, "%02x" * 2, "%02x" * 2,
                      "%02x" * 6]) % tuple(u)
 
-def maxMemory(user, machine=None):
-    return 256
+MAX_MEMORY_TOTAL = 512
+MAX_MEMORY_SINGLE = 256
+MIN_MEMORY_SINGLE = 16
+MAX_DISK_TOTAL = 50
+MAX_DISK_SINGLE = 50
+MIN_DISK_SINGLE = 0.1
+MAX_VMS_TOTAL = 10
+MAX_VMS_ACTIVE = 4
+
+def getMachinesByOwner(user, machine=None):
+    """Return the machines owned by the same as a machine.
+    
+    If the machine is None, return the machines owned by the same
+    user.
+    """
+    if machine:
+        owner = machine.owner
+    else:
+        owner = user.username
+    return Machine.select_by(owner=owner)
+
+def maxMemory(user, machine=None, on=True):
+    """Return the maximum memory for a machine or a user.
+
+    If machine is None, return the memory available for a new 
+    machine.  Else, return the maximum that machine can have.
+
+    on is whether the machine should be turned on.  If false, the max
+    memory for the machine to change to, if it is left off, is
+    returned.
+    """
+    if not on:
+        return MAX_MEMORY_SINGLE
+    machines = getMachinesByOwner(user, machine)
+    active_machines = [x for x in machines if g.uptimes[x]]
+    mem_usage = sum([x.memory for x in active_machines if x != machine])
+    return min(MAX_MEMORY_SINGLE, MAX_MEMORY_TOTAL-mem_usage)
 
 def maxDisk(user, machine=None):
-    return 10.0
+    machines = getMachinesByOwner(user, machine)
+    disk_usage = sum([sum([y.size for y in x.disks])
+                      for x in machines if x != machine])
+    return min(MAX_DISK_SINGLE, MAX_DISK_TOTAL-disk_usage/1024.)
 
-def haveAccess(user, machine):
-    return True
+def canAddVm(user):
+    machines = getMachinesByOwner(user)
+    active_machines = [x for x in machines if g.uptimes[x]]
+    return (len(machines) < MAX_VMS_TOTAL and
+            len(active_machines) < MAX_VMS_ACTIVE)
 
-def error(op, user, fields, err):
-    d = dict(op=op, user=user, errorMessage=str(err))
-    print Template(file='error.tmpl', searchList=d);
+def haveAccess(user, machine):
+    """Return whether a user has adminstrative access to a machine"""
+    if user.username == 'moo':
+        return True
+    if user.username in (machine.administrator, machine.owner):
+        return True
+    if getafsgroups.checkAfsGroup(user.username, machine.administrator, 'athena.mit.edu'): #XXX Cell?
+        return True
+    if getafsgroups.checkLockerOwner(user.username, machine.owner):
+        return True
+    return owns(user, machine)
+
+def owns(user, machine):
+    """Return whether a user owns a machine"""
+    if user.username == 'moo':
+        return True
+    return getafsgroups.checkLockerOwner(user.username, machine.owner)
+
+def error(op, user, fields, err, emsg):
+    """Print an error page when a CodeError occurs"""
+    d = dict(op=op, user=user, errorMessage=str(err),
+             stderr=emsg)
+    return Template(file='error.tmpl', searchList=[d, global_dict]);
+
+def invalidInput(op, user, fields, err, emsg):
+    """Print an error page when an InvalidInput exception occurs"""
+    d = dict(op=op, user=user, err_field=err.err_field,
+             err_value=str(err.err_value), stderr=emsg,
+             errorMessage=str(err))
+    return Template(file='invalid.tmpl', searchList=[d, global_dict]);
 
 def validMachineName(name):
     """Check that name is valid for a machine name"""
@@ -54,7 +163,10 @@ def validMachineName(name):
     charset = string.ascii_letters + string.digits + '-_'
     if name[0] in '-_' or len(name) > 22:
         return False
-    return all(x in charset for x in name)
+    for x in name:
+        if x not in charset:
+            return False
+    return True
 
 def kinit(username = 'tabbott/extra', keytab = '/etc/tabbott.keytab'):
     """Kinit with a given username and keytab"""
@@ -63,7 +175,7 @@ def kinit(username = 'tabbott/extra', keytab = '/etc/tabbott.keytab'):
                          stderr=subprocess.PIPE)
     e = p.wait()
     if e:
-        raise MyException("Error %s in kinit: %s" % (e, p.stderr.read()))
+        raise CodeError("Error %s in kinit: %s" % (e, p.stderr.read()))
 
 def checkKinit():
     """If we lack tickets, kinit."""
@@ -82,15 +194,23 @@ def remctl(*args, **kws):
                          stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE)
     if kws.get('err'):
+        p.wait()
         return p.stdout.read(), p.stderr.read()
     if p.wait():
-        print >> sys.stderr, 'ERROR on remctl ', args
+        print >> sys.stderr, 'Error on remctl', args, ':'
         print >> sys.stderr, p.stderr.read()
+        raise CodeError('ERROR on remctl')
     return p.stdout.read()
 
-def makeDisks():
-    """Update the lvm partitions to include all disks in the database."""
-    remctl('web', 'lvcreate')
+def lvcreate(machine, disk):
+    """Create a single disk for a machine"""
+    remctl('web', 'lvcreate', machine.name,
+           disk.guest_device_name, str(disk.size))
+    
+def makeDisks(machine):
+    """Update the lvm partitions to add a disk."""
+    for disk in machine.disks:
+        lvcreate(machine, disk)
 
 def bootMachine(machine, cdtype):
     """Boot a machine with a given boot CD.
@@ -99,10 +219,10 @@ def bootMachine(machine, cdtype):
     id of the CD (e.g. 'gutsy_i386')
     """
     if cdtype is not None:
-        remctl('web', 'vmboot', machine.name,
+        remctl('control', machine.name, 'create', 
                cdtype)
     else:
-        remctl('web', 'vmboot', machine.name)
+        remctl('control', machine.name, 'create')
 
 def registerMachine(machine):
     """Register a machine to be controlled by the web interface"""
@@ -136,30 +256,33 @@ def parseStatus(s):
             stack[-1].extend(v.split())
     return stack[-1]
 
-def getUptimes(machines):
+def getUptimes(machines=None):
     """Return a dictionary mapping machine names to uptime strings"""
     value_string = remctl('web', 'listvms')
     lines = value_string.splitlines()
     d = {}
-    for line in lines[1:]:
+    for line in lines:
         lst = line.split()
         name, id = lst[:2]
         uptime = ' '.join(lst[2:])
         d[name] = uptime
-    return d
+    ans = {}
+    for m in machines:
+        ans[m] = d.get(m.name)
+    return ans
 
 def statusInfo(machine):
     """Return the status list for a given machine.
 
     Gets and parses xm list --long
     """
-    value_string, err_string = remctl('list-long', machine.name, err=True)
+    value_string, err_string = remctl('control', machine.name, 'list-long', err=True)
     if 'Unknown command' in err_string:
-        raise MyException("ERROR in remctl list-long %s is not registered" % (machine.name,))
+        raise CodeError("ERROR in remctl list-long %s is not registered" % (machine.name,))
     elif 'does not exist' in err_string:
         return None
     elif err_string:
-        raise MyException("ERROR in remctl list-long %s:  %s" % (machine.name, err_string))
+        raise CodeError("ERROR in remctl list-long %s:  %s" % (machine.name, err_string))
     status = parseStatus(value_string)
     return status
 
@@ -178,6 +301,14 @@ def createVm(user, name, memory, disk, is_hvm, cdrom):
     # put stuff in the table
     transaction = ctx.current.create_transaction()
     try:
+        if memory > maxMemory(user):
+            raise InvalidInput('memory', memory,
+                               "Max %s" % maxMemory(user))
+        if disk > maxDisk(user) * 1024:
+            raise InvalidInput('disk', disk,
+                               "Max %s" % maxDisk(user))
+        if not canAddVm(user):
+            raise InvalidInput('create', True, 'Unable to create more VMs')
         res = meta.engine.execute('select nextval(\'"machines_machine_id_seq"\')')
         id = res.fetchone()[0]
         machine = Machine()
@@ -185,6 +316,7 @@ def createVm(user, name, memory, disk, is_hvm, cdrom):
         machine.name = name
         machine.memory = memory
         machine.owner = user.username
+        machine.administrator = user.username
         machine.contact = user.email
         machine.uuid = uuidToString(randomUUID())
         machine.boot_off_cd = True
@@ -195,7 +327,7 @@ def createVm(user, name, memory, disk, is_hvm, cdrom):
                     'hda', disk)
         open = NIC.select_by(machine_id=None)
         if not open: #No IPs left!
-            return "No IP addresses left!  Contact sipb-xen-dev@mit.edu"
+            raise CodeError("No IP addresses left!  Contact sipb-xen-dev@mit.edu")
         nic = open[0]
         nic.machine_id = machine.machine_id
         nic.hostname = name
@@ -205,91 +337,125 @@ def createVm(user, name, memory, disk, is_hvm, cdrom):
     except:
         transaction.rollback()
         raise
-    makeDisks()
     registerMachine(machine)
+    makeDisks(machine)
     # tell it to boot with cdrom
     bootMachine(machine, cdrom)
 
     return machine
 
-def create(user, fields):
-    name = fields.getfirst('name')
-    if not validMachineName(name):
-        raise MyException("Invalid name '%s'" % name)
-    name = user.username + '_' + name.lower()
+def validMemory(user, memory, machine=None, on=True):
+    """Parse and validate limits for memory for a given user and machine.
 
-    if Machine.get_by(name=name):
-        raise MyException("A machine named '%s' already exists" % name)
-    
-    memory = fields.getfirst('memory')
+    on is whether the memory must be valid after the machine is
+    switched on.
+    """
     try:
         memory = int(memory)
-        if memory <= 0:
+        if memory < MIN_MEMORY_SINGLE:
             raise ValueError
     except ValueError:
-        raise MyException("Invalid memory amount")
-    if memory > maxMemory(user):
-        raise MyException("Too much memory requested")
-    
-    disk = fields.getfirst('disk')
+        raise InvalidInput('memory', memory, 
+                           "Minimum %s MB" % MIN_MEMORY_SINGLE)
+    if memory > maxMemory(user, machine, on):
+        raise InvalidInput('memory', memory,
+                           'Maximum %s MB' % maxMemory(user, machine))
+    return memory
+
+def validDisk(user, disk, machine=None):
+    """Parse and validate limits for disk for a given user and machine."""
     try:
         disk = float(disk)
-        if disk > maxDisk(user):
-            raise MyException("Too much disk requested")
+        if disk > maxDisk(user, machine):
+            raise InvalidInput('disk', disk,
+                               "Maximum %s G" % maxDisk(user, machine))
         disk = int(disk * 1024)
-        if disk <= 0:
+        if disk < MIN_DISK_SINGLE * 1024:
             raise ValueError
     except ValueError:
-        raise MyException("Invalid disk amount")
+        raise InvalidInput('disk', disk,
+                           "Minimum %s GB" % MIN_DISK_SINGLE)
+    return disk
+
+def create(user, fields):
+    """Handler for create requests."""
+    name = fields.getfirst('name')
+    if not validMachineName(name):
+        raise InvalidInput('name', name)
+    name = name.lower()
+
+    if Machine.get_by(name=name):
+        raise InvalidInput('name', name,
+                           "Already exists")
+    
+    memory = fields.getfirst('memory')
+    memory = validMemory(user, memory, on=True)
     
+    disk = fields.getfirst('disk')
+    disk = validDisk(user, disk)
+
     vm_type = fields.getfirst('vmtype')
     if vm_type not in ('hvm', 'paravm'):
-        raise MyException("Invalid vm type '%s'"  % vm_type)    
+        raise CodeError("Invalid vm type '%s'"  % vm_type)    
     is_hvm = (vm_type == 'hvm')
 
     cdrom = fields.getfirst('cdrom')
     if cdrom is not None and not CDROM.get(cdrom):
-        raise MyException("Invalid cdrom type '%s'" % cdrom)    
+        raise CodeError("Invalid cdrom type '%s'" % cdrom)    
     
     machine = createVm(user, name, memory, disk, is_hvm, cdrom)
-    if isinstance(machine, basestring):
-        raise MyException(machine)
     d = dict(user=user,
              machine=machine)
-    print Template(file='create.tmpl',
-                   searchList=d);
+    return Template(file='create.tmpl',
+                   searchList=[d, global_dict]);
 
 def listVms(user, fields):
-    machines = Machine.select()
+    """Handler for list requests."""
+    machines = [m for m in Machine.select() if haveAccess(user, m)]    
     on = {}
     has_vnc = {}
-    uptimes = getUptimes(machines)
-    on = has_vnc = uptimes
+    on = g.uptimes
+    for m in machines:
+        if not on[m]:
+            has_vnc[m] = 'Off'
+        elif m.type.hvm:
+            has_vnc[m] = True
+        else:
+            has_vnc[m] = "ParaVM"+helppopup("paravm_console")
     #     for m in machines:
     #         status = statusInfo(m)
     #         on[m.name] = status is not None
     #         has_vnc[m.name] = hasVnc(status)
+    max_mem=maxMemory(user)
+    max_disk=maxDisk(user)
     d = dict(user=user,
-             maxmem=maxMemory(user),
-             maxdisk=maxDisk(user),
+             can_add_vm=canAddVm(user),
+             max_mem=max_mem,
+             max_disk=max_disk,
+             default_mem=max_mem,
+             default_disk=min(4.0, max_disk),
              machines=machines,
              has_vnc=has_vnc,
-             uptimes=uptimes,
+             uptimes=g.uptimes,
              cdroms=CDROM.select())
-    print Template(file='list.tmpl', searchList=d)
+    return Template(file='list.tmpl', searchList=[d, global_dict])
 
 def testMachineId(user, machineId, exists=True):
+    """Parse, validate and check authorization for a given machineId.
+
+    If exists is False, don't check that it exists.
+    """
     if machineId is None:
-        raise MyException("No machine ID specified")
+        raise CodeError("No machine ID specified")
     try:
         machineId = int(machineId)
     except ValueError:
-        raise MyException("Invalid machine ID '%s'" % machineId)
+        raise CodeError("Invalid machine ID '%s'" % machineId)
     machine = Machine.get(machineId)
     if exists and machine is None:
-        raise MyException("No such machine ID '%s'" % machineId)
-    if not haveAccess(user, machine):
-        raise MyException("No access to machine ID '%s'" % machineId)
+        raise CodeError("No such machine ID '%s'" % machineId)
+    if machine is not None and not haveAccess(user, machine):
+        raise CodeError("No access to machine ID '%s'" % machineId)
     return machine
 
 def vnc(user, fields):
@@ -305,9 +471,11 @@ def vnc(user, fields):
     -t nat -A PREROUTING -s ! 18.181.0.60 -i eth1 -p tcp -m tcp --dport 10003 -j DNAT --to-destination 18.181.0.60:10003 
     -t nat -A POSTROUTING -d 18.181.0.60 -o eth1 -p tcp -m tcp --dport 10003 -j SNAT --to-source 18.187.7.142 
     -A FORWARD -d 18.181.0.60 -i eth1 -o eth1 -p tcp -m tcp --dport 10003 -j ACCEPT
+
+    Remember to enable iptables!
+    echo 1 > /proc/sys/net/ipv4/ip_forward
     """
     machine = testMachineId(user, fields.getfirst('machine_id'))
-    #XXX fix
     
     TOKEN_KEY = "0M6W0U1IXexThi5idy8mnkqPKEq1LtEnlK/pZSn0cDrN"
 
@@ -322,14 +490,24 @@ def vnc(user, fields):
     token = cPickle.dumps(token)
     token = base64.urlsafe_b64encode(token)
     
+    status = statusInfo(machine)
+    has_vnc = hasVnc(status)
+    
     d = dict(user=user,
+             on=status,
+             has_vnc=has_vnc,
              machine=machine,
              hostname=os.environ.get('SERVER_NAME', 'localhost'),
              authtoken=token)
-    print Template(file='vnc.tmpl',
-                   searchList=d)
+    return Template(file='vnc.tmpl',
+                   searchList=[d, global_dict])
 
 def getNicInfo(data_dict, machine):
+    """Helper function for info, get data on nics for a machine.
+
+    Modifies data_dict to include the relevant data, and returns a list
+    of (key, name) pairs to display "name: data_dict[key]" to the user.
+    """
     data_dict['num_nics'] = len(machine.nics)
     nic_fields_template = [('nic%s_hostname', 'NIC %s hostname'),
                            ('nic%s_mac', 'NIC %s MAC Addr'),
@@ -346,6 +524,11 @@ def getNicInfo(data_dict, machine):
     return nic_fields
 
 def getDiskInfo(data_dict, machine):
+    """Helper function for info, get data on disks for a machine.
+
+    Modifies data_dict to include the relevant data, and returns a list
+    of (key, name) pairs to display "name: data_dict[key]" to the user.
+    """
     data_dict['num_disks'] = len(machine.disks)
     disk_fields_template = [('%s_size', '%s size')]
     disk_fields = []
@@ -356,6 +539,8 @@ def getDiskInfo(data_dict, machine):
     return disk_fields
 
 def deleteVM(machine):
+    """Delete a VM."""
+    remctl('control', machine.name, 'destroy', err=True)
     transaction = ctx.current.create_transaction()
     delete_disk_pairs = [(machine.name, d.guest_device_name) for d in machine.disks]
     try:
@@ -375,64 +560,217 @@ def deleteVM(machine):
     unregisterMachine(machine)
 
 def command(user, fields):
-    print time.time()-start_time
+    """Handler for running commands like boot and delete on a VM."""
+    print >> sys.stderr, time.time()-start_time
     machine = testMachineId(user, fields.getfirst('machine_id'))
     action = fields.getfirst('action')
     cdrom = fields.getfirst('cdrom')
-    print time.time()-start_time
+    print >> sys.stderr, time.time()-start_time
     if cdrom is not None and not CDROM.get(cdrom):
-        raise MyException("Invalid cdrom type '%s'" % cdrom)    
+        raise CodeError("Invalid cdrom type '%s'" % cdrom)    
     if action not in ('Reboot', 'Power on', 'Power off', 'Shutdown', 'Delete VM'):
-        raise MyException("Invalid action '%s'" % action)
+        raise CodeError("Invalid action '%s'" % action)
     if action == 'Reboot':
         if cdrom is not None:
-            remctl('reboot', machine.name, cdrom)
+            remctl('control', machine.name, 'reboot', cdrom)
         else:
-            remctl('reboot', machine.name)
+            remctl('control', machine.name, 'reboot')
     elif action == 'Power on':
+        if maxMemory(user) < machine.memory:
+            raise InvalidInput('action', 'Power on',
+                               "You don't have enough free RAM quota to turn on this machine")
         bootMachine(machine, cdrom)
     elif action == 'Power off':
-        remctl('destroy', machine.name)
+        remctl('control', machine.name, 'destroy')
     elif action == 'Shutdown':
-        remctl('shutdown', machine.name)
+        remctl('control', machine.name, 'shutdown')
     elif action == 'Delete VM':
         deleteVM(machine)
-    print time.time()-start_time
+    print >> sys.stderr, time.time()-start_time
 
     d = dict(user=user,
              command=action,
              machine=machine)
-    print Template(file="command.tmpl", searchList=d)
-        
+    return Template(file="command.tmpl", searchList=[d, global_dict])
+
+def testAdmin(user, admin, machine):
+    if admin in (None, machine.administrator):
+        return None
+    if admin == user.username:
+        return admin
+    if getafsgroups.checkAfsGroup(user.username, admin, 'athena.mit.edu'):
+        return admin
+    if getafsgroups.checkAfsGroup(user.username, 'system:'+admin, 'athena.mit.edu'):
+        return 'system:'+admin
+    raise InvalidInput('admin', admin, 
+                       'You must control the group you move it to')
+    
+def testOwner(user, owner, machine):
+    if owner in (None, machine.owner):
+        return None
+    #XXX should you be able to transfer ownership if you don't already own it?
+    #if not owns(user, machine):
+    #    raise InvalidInput('owner', owner, "You don't own this machine, so you can't  transfer ownership")
+    value = getafsgroups.checkLockerOwner(user.username, owner, verbose=True)
+    if value == True:
+        return owner
+    raise InvalidInput('owner', owner, value)
+
+def testContact(user, contact, machine=None):
+    if contact in (None, machine.contact):
+        return None
+    if not re.match("^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$", contact, re.I):
+        raise InvalidInput('contact', contact, "Not a valid email")
+    return contact
+
+def testDisk(user, disksize, machine=None):
+    return disksize
+
+def testName(user, name, machine=None):
+    if name in (None, machine.name):
+        return None
+    if not Machine.select_by(name=name):
+        return name
+    raise InvalidInput('name', name, "Already taken")
+
+def testHostname(user, hostname, machine):
+    for nic in machine.nics:
+        if hostname == nic.hostname:
+            return hostname
+    # check if doesn't already exist
+    if NIC.select_by(hostname=hostname):
+        raise InvalidInput('hostname', hostname,
+                           "Already exists")
+    if not re.match("^[A-Z0-9-]{1,22}$", hostname, re.I):
+        raise InvalidInput('hostname', hostname, "Not a valid hostname; must only use number, letters, and dashes.")
+    return hostname
+
 def modify(user, fields):
-    machine = testMachineId(user, fields.getfirst('machine_id'))
+    """Handler for modifying attributes of a machine."""
+
+    olddisk = {}
+    transaction = ctx.current.create_transaction()
+    try:
+        machine = testMachineId(user, fields.getfirst('machine_id'))
+        owner = testOwner(user, fields.getfirst('owner'), machine)
+        admin = testAdmin(user, fields.getfirst('administrator'), machine)
+        contact = testContact(user, fields.getfirst('contact'), machine)
+        hostname = testHostname(owner, fields.getfirst('hostname'), machine)
+        name = testName(user, fields.getfirst('name'), machine)
+        oldname = machine.name
+        command="modify"
+
+        memory = fields.getfirst('memory')
+        if memory is not None:
+            memory = validMemory(user, memory, machine, on=False)
+            machine.memory = memory
+ 
+        disksize = testDisk(user, fields.getfirst('disk'))
+        if disksize is not None:
+            disksize = validDisk(user, disksize, machine)
+            disk = machine.disks[0]
+            if disk.size != disksize:
+                olddisk[disk.guest_device_name] = disksize
+                disk.size = disksize
+                ctx.current.save(disk)
+        
+        # XXX first NIC gets hostname on change?  Interface doesn't support more.
+        for nic in machine.nics[:1]:
+            nic.hostname = hostname
+            ctx.current.save(nic)
+
+        if owner is not None:
+            machine.owner = owner
+        if name is not None:
+            machine.name = name
+        if admin is not None:
+            machine.administrator = admin
+        if contact is not None:
+            machine.contact = contact
+            
+        ctx.current.save(machine)
+        transaction.commit()
+    except:
+        transaction.rollback()
+        raise
+    for diskname in olddisk:
+        remctl("web", "lvresize", oldname, diskname, str(olddisk[diskname]))
+    if name is not None:
+        for disk in machine.disks:
+            remctl("web", "lvrename", oldname, disk.guest_device_name, name)
+        remctl("web", "moveregister", oldname, name)
+    d = dict(user=user,
+             command=command,
+             machine=machine)
+    return Template(file="command.tmpl", searchList=[d, global_dict])    
+
+
+def help(user, fields):
+    """Handler for help messages."""
+    simple = fields.getfirst('simple')
+    subjects = fields.getlist('subject')
+    
+    mapping = dict(paravm_console="""
+ParaVM machines do not support console access over VNC.  To access
+these machines, you either need to boot with a liveCD and ssh in or
+hope that the sipb-xen maintainers add support for serial consoles.""",
+                   hvm_paravm="""
+HVM machines use the virtualization features of the processor, while
+ParaVM machines use Xen's emulation of virtualization features.  You
+want an HVM virtualized machine.""",
+                   cpu_weight="""Don't ask us!  We're as mystified as you are.""",
+                   owner="""The owner field is used to determine <a href="help?subject=quotas">quotas</a>.  It must be the name
+of a locker that you are an AFS administrator of.  In particular, you
+or an AFS group you are a member of must have AFS rlidwka bits on the
+locker.  You can check see who administers the LOCKER locker using the
+command 'fs la /mit/LOCKER' on Athena.)  See also <a href="help?subject=administrator">administrator</a>.""",
+                   administrator="""The administrator field determines who can access the console and power on and off the machine.  This can be either a user or a moira group.""",
+                   quotas="""Quotas are determined on a per-locker basis.  Each 
+quota may have a maximum of 512 megabytes of active ram, 50 gigabytes of disk, and 4 active machines."""
+
+                   )
+    
+    if not subjects:
+        subjects = sorted(mapping.keys())
+        
+    d = dict(user=user,
+             simple=simple,
+             subjects=subjects,
+             mapping=mapping)
+    
+    return Template(file="help.tmpl", searchList=[d, global_dict])
     
 
 def info(user, fields):
+    """Handler for info on a single VM."""
     machine = testMachineId(user, fields.getfirst('machine_id'))
     status = statusInfo(machine)
     has_vnc = hasVnc(status)
     if status is None:
         main_status = dict(name=machine.name,
                            memory=str(machine.memory))
+        uptime=None
+        cputime=None
     else:
         main_status = dict(status[1:])
-    start_time = float(main_status.get('start_time', 0))
-    uptime = datetime.timedelta(seconds=int(time.time()-start_time))
-    cpu_time_float = float(main_status.get('cpu_time', 0))
-    cputime = datetime.timedelta(seconds=int(cpu_time_float))
+        start_time = float(main_status.get('start_time', 0))
+        uptime = datetime.timedelta(seconds=int(time.time()-start_time))
+        cpu_time_float = float(main_status.get('cpu_time', 0))
+        cputime = datetime.timedelta(seconds=int(cpu_time_float))
     display_fields = """name uptime memory state cpu_weight on_reboot 
      on_poweroff on_crash on_xend_start on_xend_stop bootloader""".split()
     display_fields = [('name', 'Name'),
                       ('owner', 'Owner'),
+                      ('administrator', 'Administrator'),
                       ('contact', 'Contact'),
+                      ('type', 'Type'),
                       'NIC_INFO',
                       ('uptime', 'uptime'),
                       ('cputime', 'CPU usage'),
                       ('memory', 'RAM'),
                       'DISK_INFO',
                       ('state', 'state (xen format)'),
-                      ('cpu_weight', 'CPU weight'),
+                      ('cpu_weight', 'CPU weight'+helppopup('cpu_weight')),
                       ('on_reboot', 'Action on VM reboot'),
                       ('on_poweroff', 'Action on VM poweroff'),
                       ('on_crash', 'Action on VM crash'),
@@ -442,7 +780,10 @@ def info(user, fields):
                       ]
     fields = []
     machine_info = {}
+    machine_info['name'] = machine.name
+    machine_info['type'] = machine.type.hvm and 'HVM' or 'ParaVM'
     machine_info['owner'] = machine.owner
+    machine_info['administrator'] = machine.administrator
     machine_info['contact'] = machine.contact
 
     nic_fields = getNicInfo(machine_info, machine)
@@ -455,16 +796,17 @@ def info(user, fields):
     
     main_status['memory'] += ' MB'
     for field, disp in display_fields:
-        if field in ('uptime', 'cputime'):
+        if field in ('uptime', 'cputime') and locals()[field] is not None:
             fields.append((disp, locals()[field]))
-        elif field in main_status:
-            fields.append((disp, main_status[field]))
         elif field in machine_info:
             fields.append((disp, machine_info[field]))
+        elif field in main_status:
+            fields.append((disp, main_status[field]))
         else:
             pass
             #fields.append((disp, None))
-
+    max_mem = maxMemory(user, machine)
+    max_disk = maxDisk(user, machine)
     d = dict(user=user,
              cdroms=CDROM.select(),
              on=status is not None,
@@ -472,18 +814,20 @@ def info(user, fields):
              has_vnc=has_vnc,
              uptime=str(uptime),
              ram=machine.memory,
-             maxmem=maxMemory(user, machine),
-             maxdisk=maxDisk(user, machine),
+             max_mem=max_mem,
+             max_disk=max_disk,
+             owner_help=helppopup("owner"),
              fields = fields)
-    print Template(file='info.tmpl',
-                   searchList=d)
+    return Template(file='info.tmpl',
+                   searchList=[d, global_dict])
 
 mapping = dict(list=listVms,
                vnc=vnc,
                command=command,
                modify=modify,
                info=info,
-               create=create)
+               create=create,
+               help=help)
 
 if __name__ == '__main__':
     start_time = time.time()
@@ -492,22 +836,59 @@ if __name__ == '__main__':
         username = "moo"
         email = 'moo@cow.com'
     u = User()
+    g = Global(u)
+    if 'SSL_CLIENT_S_DN_Email' in os.environ:
+        username = os.environ[ 'SSL_CLIENT_S_DN_Email'].split("@")[0]
+        u.username = username
+        u.email = os.environ[ 'SSL_CLIENT_S_DN_Email']
+    else:
+        u.username = 'moo'
+        u.email = 'nobody'
     connect('postgres://sipb-xen@sipb-xen-dev/sipb_xen')
     operation = os.environ.get('PATH_INFO', '')
     if not operation:
-        pass
-        #XXX do redirect
+        print "Status: 301 Moved Permanently"
+        print 'Location: ' + os.environ['SCRIPT_NAME']+'/\n'
+        sys.exit(0)
 
     if operation.startswith('/'):
         operation = operation[1:]
     if not operation:
         operation = 'list'
-    
-    fun = mapping.get(operation, 
-                      lambda u, e:
-                          error(operation, u, e,
-                                "Invalid operation '%s'" % operation))
+
+    def badOperation(u, e):
+        raise CodeError("Unknown operation")
+
+    fun = mapping.get(operation, badOperation)
+    if fun not in (help, ):
+        connect('postgres://sipb-xen@sipb-xen-dev/sipb_xen')
     try:
-        fun(u, fields)
-    except MyException, err:
-        error(operation, u, fields, err)
+        output = fun(u, fields)
+        print 'Content-Type: text/html\n'
+        sys.stderr=sys.stdout
+        errio.seek(0)
+        e = errio.read()
+        if e:
+            output = str(output)
+            output = output.replace('<body>', '<body><p>STDERR:</p><pre>'+e+'</pre>')
+        print output
+    except CodeError, err:
+        print 'Content-Type: text/html\n'
+        sys.stderr=sys.stdout
+        errio.seek(0)
+        e = errio.read()
+        print error(operation, u, fields, err, e)
+    except InvalidInput, err:
+        print 'Content-Type: text/html\n'
+        sys.stderr=sys.stdout
+        errio.seek(0)
+        e = errio.read()
+        print invalidInput(operation, u, fields, err, e)
+    except:
+        print 'Content-Type: text/plain\n'
+        sys.stderr=sys.stdout
+        errio.seek(0)
+        e = errio.read()
+        print e
+        print '----'
+        raise